Hi my 2 6 & 7ft new zealand flax have been flattened by the snow this winter i have removed all the dead flax however the plant is still flat and alot of the leaves are orangey and half dead .Can i cut it right back to the base (a task that will take a life time considring their size )and will it grow back??

Could be anywhere at the base, nearest the ground - sometimes appears at the base of other leaves, and if you're not careful, you find you've chopped the tip off the new leaf along with the damaged ones you're trying to remove.